This is a quick top-of-the-head proof of concept of a flapping, flying bird animation. It was easier than I thought. Integrating this with a responsive layout, using SVG assets will be a bit more challenging but very doable. This is part of the testing phase of a layout with several independent, lightweight CSS animations.

This is the simplest possible implementation for a sticky footer done purely in CSS. No js trickery. The craziest thing is the psuedo :after on #wrapper, but it should still be cross-browser compatible all the way down through IE8. IE6-7 do not support psuedo selectors.
It will keep your footer at the bottom of the page no matter how much or little vertical space exists, but scrolls away. It's not the same as a fixed footer.
I added a #content div with a few things and some padding just to make it look like something. None of that is necessary. It will work with an empty #wrapper. Important thing is to keep your footer element outside your wrapper, make sure the :after has the content and display attributes set as shown, the footer height and #wrapper:after can be set at the same time to save a little typing, but is not necessary. It's important to make sure the negative bottom margin of the #wrapper is set to the total box height. I have a 1px border at the top of my #footer so the negative #wrapper margin needs to be 51px. Works with class, id, or footer css3 tag.

This is easier than it looks! The animation is pretty self-explanatory. You can adapt it to any type of vector. Add more layers and colors. Making slight adjustments to transform-origin and animation-duration on individual elements will give nice offset effects. In my example, the addition of an extra .5s to one of the flame layers gives it the illusion its different from the other flame but it uses the exact same animation, just a little slower. Thanks so much to gist.github.com/oddlyzen/1229700 for the inspiration for the flicker animation :)

This is the simplest possible implementation of a sticky footer using Flexbox. The height of the footer and header are not static and the 'main' element will always take up the available space and will grow if more content is added.